Feeler gauge



1937. A. J. BRICKNER 2,090,178

FEELER GAUGE Filed Jan. 15, 1936 Wm mm? Meme Patented Aug. 17, 1937UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to a feeler or tracer adapted to be usedprincipally on duplicating machines, by means of which parts areduplicated from and in accordance with following a prepared model orpattern. Feelers or tracers of this character may be used in manyrelations and with the device Which I have constructed, it is sodesigned and arranged that as soon as the projecting feeler pointerthereof comes into contact with a surface point of the model or pattern,an electric circuit is closed, which operates either directly or througha suitable relay, to the control of the duplicating mechanism, forexample, it may be used to control the motion of the feeds of theduplicating machine; or the feeler or tracer may be used for actuating asignal such as lighting a small electric light, ringing a bell, or thelike.

Feelers or tracers of the character noted operate within very smalllimits of dimension and are, therefore, in operation respects of adelicate character. With my invention, notwithstanding the delicacy ofthe feeler operation the device is sturdy and not likely to be thrownout of ad- 25 justment even upon long and hard use. One very decidedadvantage of this tracer or feeler is that, irrespective of the angle ofcontact of the feeler finger or pointer relative to the model or patternagainst which it engages, the circuit will be closed and the effects ofthe designed circuit closing follow.

One construction embodying my invention is shown in the accompanyingdrawing, in which,

Fig. 1 is a side elevation of the feeler or tracer of my inventionillustrating it in use as contacting with an irregular surface of amodel or pattern.

Fig. 2 is a central longitudinal section through the feeler, and

Fig. 3 is a similar fragmentary section at the pointer end thereofshowing the operation of the same when the pointer is slightly turned atan angle to its longitudinal axis.

Like reference characters refer to like parts in the different figuresof the drawing.

In the construction, a tube of uniform diameter is provided exteriorlythreaded at what may be termed its rear end, over which a cap 2 isscrewed, in the bottom of which is an opening 3. The other end of thetube l is interiorly threaded and is closed by a member 4 which has acentral opening 5 and from which at the inner side an integralexteriorly threaded sleeve 6 extends, the sleeve being formed at itsinner end with curved surfaces at l which provide a curved ll passes,the front end thereof being equipped 10 with a disk-like head l2,between which and the block 8 and surrounding the guide 9 is acompression spring IS, the tendency of which is to move head l2 and rodI! in a forward direction, that is, to the right, looking at Fig. 2.

A member having a head 14 with a spherical forward surface has a flatrear side to bear against the outer or forward side of the disk head I2. The curved surface of the part I4 bears against the complementarycurved surface 1 previously described, being held thereagainst by thepressure of the spring l3. A stem l5 having a diameter slightly lessthan the diameter of the opening 5 in the member 4 extends from the headM in axial alinement with the rod I l and through the opening 5. At itsouter or forward end a pointer [6 may be detachably secured. The methodof attachment is fully illustrated in Fig. 2. Different pointers havingdifferent shapes at their outer ends and of different lengths may beused as the type or character of the work to be done may require.

Back of the block 8 and within the tube l a tubular member I! is securedin place by a set screw l8 (see Fig. 2). It may be adjusted to a desiredposition and then rigidly secured against movement. A multiplyingflexible lever l9 extends lengthwise of and within the tubular memberIT, at its forward end having downwardly projecting ears. 2E: which arepivotally connected to an inwardly extending lug 2| struck from orintegral with the tubular member ll. The forward end of the movablelever I9 is rounded and bears against the rear end of the rod H againstwhich it is held by a coiled spring 22 under compression, which islocated between the under side of the lever l9 and the adjacent underportion of the tubular member IT.

The movable lever 9, at its rear end, carries a contact 23 at itsunderside which is positioned directly above a second contact 24 securedto a metal bar 25, which in turn is carried by a sleeve 26 of electricinsulating material threaded into the rear end of the tubular member H.A circuit wire 21 is connected in any suitable manner to the rear end ofthe bar 25, see Fig. 2.

It is apparent that a slight rearward movement of the rod II causes thecontact 23 to be moved downwardly to engage the contact 24. The voltagein the electric circuit is low whereby when the contacts 23 and 24 aretogether the body I of the tool may serve as a ground for the circuit. Arearward movement of a very small amount, measured in thousandths of aninch, causes an engagement of the contacts 23 and 24 and a clos ing ofthe circuit which, either directly or through a suitable relay, may beused to control duplieating machinery, or may be used to close a circuitfor energizing a signal or alarm.

In Fig. l the feeler or tracer is shown mounted upon a support 28 whichmay be moved toward and away from a pattern or model 29 having a surface30 with which the free end of the pointer I9 is to engage. When thesupport 28 is moved toward the pattern 29 as soon as the end of thepointer I6 engages a point of the surface 39, the pointer I6 andassociated parts are moved either directly back or tilted as shown inFig. 3. In either case a slight movement of the pointer closes thecircuit by bringing the contacts 23 and 2 together and sets in operationwhatever sequence of operations or results follows from such circuitclosing as previously described.

It is apparent that the tubular member I! with the insulating sleeve 26therein carrying the contact 24, and with a multiplying lever I9pivotally mounted may be assembled as a unit and readily inserted intothe rear end of the tube I until the rounded end of the lever I9 engagesthe rear end of the rod I I, and then by adjustment the spacing of thecontacts 23 and 24 may be controlled so as to have the space the amountdesired. By reason of the relatively large movement given to the movablelever I9 following from a very short longitudinal movement of the rod II, the contacts 23 and 24 may be brought together by a movement of therod II measured as a very minute distance.

The structure described is sturdy and reliable and capable ofwithstanding severe usage without getting out of order.

The invention is defined in the appended claims and is to be consideredcomprehensive of all forms of structure coming within their scope.

I claim:

1. In a precision measuring instrument of the class described,comprising, a body of cylindrical shape, open at the ends, said bodyhaving fastening means at each end, a plug member having a sphericalseat interiorly thereof at one end and a restricted opening ofpredetermined size at its other end, a rod having a semi-spherical headadapted to be universally mounted within said seat, said plug memberhaving fastening means cooperatively associated with the first mentionedfastening means, the rod passing through the said restricted opening, ablock, having an outer diameter substantially equal with the innerdiameter of the said body member and having an axial openingtherethrough, located within the said body member, means for mountingthe same adjacent the plug member, a rod, having a disk head, slidablymounted in the said axial opening with its head closely positioned tothe flat side of the semi-spherical member, spring means located betweenthe block and the disk head whereby the disk head urges the rod toextended position, means, including a multiplying lever adapted to becooperatively associated with the said rod, cap means, engageable withthe fastening means on the other end of said body, for holding the lastmentioned means in position.

2. An article of manufacture of the class described comprising acylindrical hollow body member, a hollow plug member located at one endthereof, said hollow plug member having its inner end shaped to form aspherical seat and its outer end having an opening therethrough, acontacting rod element extending through the said opening, asemi-spherical head attached to said rod element and receivable withinthe spherical seat for limited universal movement, a block member,having an axial opening therethrough, snugly receivable within the saidcylindrical body between its ends, means for holding it in positionrelatively thereto, a rod member slidably mounted within the openingthrough the block member, a disk on the rod at the end adjacent thesemispherical head, spring means between the disk and the block member,a tubular member likewise snugly receivable and adjustable within thebody member, a movable lever pivoted on the inner end of the tubularmember and bodily movable therewith, said lever having one portion,closely adjacent the pivot, in contact with the end of the rod and asecond portion having a contact button thereon, said contact buttonbeing located a relatively long distance from the pivot, a secondcontact button, means for mounting the second contact button on thetubular member and means engaged with the body member to hold thetubular member in position.

3. A combination of elements as set forth in claim 2 in which the meansfor mounting the second contact button includes a sleeve threaded intothe tubular member whereby axial movement of the button is had.

ARTHUR J. BRICKN'ER.

